Design for cassette holder



FIG. 1 is a perspective view of a cassette holder showing my new design, the broken lines showing cassettes are for illustrative purposes only;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a side elevational view, the opposite side being a mirror image thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a front elevational view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a cassette holder as shown and described. 